Helleborus plant named ‘COSEH210’

ABSTRACT

A new and distinct cultivar of  Helleborus  plant named ‘COSEH 210’, characterized by its upright and mounded plant habit; dark green-colored leaves; early and freely flowering habit; and large white-colored flowers.

Botanical designation: Helleborus niger.

Cultivar denomination: ‘COSEH 210’.

BACKGROUND OF THE INVENTION

The present invention relates to a new and distinct cultivar of Helleborus plant, botanically known as Helleborus niger, and hereinafter referred to by the name ‘COSEH 210’.

The new Helleborus plant is a product of a planned breeding program in Glandorf, Germany. The objective of the breeding program was to create new uniform Helleborus cultivars with unique and attractive flower coloration and resistance to pests.

The new Helleborus plant originated from a cross-pollination conducted by the Inventor in Glandorf, Germany in December, 2002 of two unnamed proprietary seedling selections of Helleborus niger, not patented. The new Helleborus plant was discovered and selected by the Inventor as a single flowering plant from within the progeny of the stated cross-pollination grown in a controlled greenhouse environment in Glandorf, Germany in November, 2004.

Asexual reproduction of the new Helleborus plant by divisions in a controlled greenhouse environment in Glandorf, Germany since February, 2005, has shown that the unique features of this new Helleborus plant are stable and reproduced true to type in successive generations.

SUMMARY OF THE INVENTION

Plants of the new Helleborus have not been observed under all possible environmental conditions. The phenotype may vary somewhat with variations in environment and cultural practices such as temperature and light intensity without, however, any variance in genotype.

The following traits have been repeatedly observed and are determined to be the unique characteristics of ‘COSEH 210’. These characteristics in combination distinguish ‘COSEH 210’ as a new and distinct cultivar of Helleborus:

-   -   1. Upright and mounded plant habit.     -   2. Dark green-colored leaves.     -   3. Early and freely flowering habit.     -   4. Large white-colored flowers.

Compared to plants of the parent selections, plants of the new Helleborus are more uniform and more freely flowering.

Plants of the new Helleborus can be compared to plants of Helleborus niger ‘HGC Josef Lemper’, disclosed in U.S. Plant Pat. No. 15,615. Plants of the new Helleborus differ primarily from plants of ‘HGC Josef Lemper’ in the following characteristics:

-   -   1. Plants of the new Helleborus have darker green-colored leaves         than plants of ‘HGC Josef Lemper’.     -   2. Plants of the new Helleborus have shorter leaf petioles than         plants of ‘HGC Josef Lemper’.     -   3. Plants of the new Helleborus flower earlier than plants of         ‘HGC Josef Lemper’.

BRIEF DESCRIPTION OF THE PHOTOGRAPH

The accompanying colored photograph illustrates the overall appearance of the new Helleborus plant, showing the colors as true as it is reasonably possible to obtain in colored reproductions of this type. Colors in the photograph may differ slightly from the color values cited in the detailed botanical description which accurately describe the colors of the new Helleborus plant.

The photograph comprises a side perspective view of a typical flowering plant of ‘COSEH 210’ grown in a container.

DETAILED BOTANICAL DESCRIPTION

The aforementioned photograph and following observations, measurements and values describe plants grown in Glandorf, Germany in 13-cm containers during the winter in an outdoor nursery and under conditions which closely approximate commercial Helleborus production. During the production of the plants, day temperatures ranged from 5° C. to 32° C. and night temperatures ranged from 1° C. to 25° C. Plants had been growing for one year when the photograph and the description were taken. In the following description, color references are made to The Royal Horticultural Society Colour Chart, 2007 Edition, except where general terms of ordinary dictionary significance are used.

-   Botanical classification: Helleborus niger ‘COSEH 210’. -   Parentage:     -   -   Female, or seed, parent.—Unnamed proprietary seedling             selection of Helleborus niger, not patented.         -   Male, or pollen, parent.—Unnamed proprietary seedling             selection of Helleborus niger, not patented. -   Propagation:     -   -   Type.—By divisions.         -   Time to initiate roots.—About 56 days at 12° C.         -   Time to produce a rooted young plant.—About five months at             4° C. to 15° C.         -   Root description.—Thick to thin, fleshy; white to brown in             color.         -   Rooting habit.—Sparse. -   Plant description:     -   -   Plant form and growth habit.—Herbaceous perennial; upright             and mounded plant habit; moderately vigorous growth habit.         -   Plant height.—About 15 cm to 20 cm.         -   Plant diameter (area of spread).—About 30 cm to 35 cm. -   Foliage description:     -   -   Arrangement.—Palmately compound with five to seven leaflets             per leaf.         -   Leaflet length.—About 4 cm to 8 cm.         -   Leaflet width.—About 1.5 cm to 4 cm.         -   Leaflet shape.—Roughly ovate.         -   Leaflet apex.—Broadly acuminate.         -   Leaflet base.—Asymmetrically acute.         -   Leaflet margin.—Serrate.         -   Leaflet texture, upper and lower surfaces.—Smooth, glabrous;             leathery.         -   Leaflet venation pattern.—Pinnate; reticulate.         -   Leaflet color.—Developing leaves, upper surface: Close to             137A. Developing leaves, lower surface: Close to 146B. Fully             developed leaves, upper surface: Close to 147A; venation,             close to 146B. Fully developed leaves, lower surface: Close             to 147B; venation, close to 146D.         -   Petiole.—Length: About 2 mm to 8 mm. Diameter: About 2 mm to             3 mm. Texture, upper and lower surfaces: Smooth, glabrous.             Color, upper and lower surfaces: Close to 144B tinged with             close to 200B. -   Flower description:     -   -   Flower shape and habit.—Single rotate flowers; freely             flowering habit, about 30 to 40 flowers developing per             plant. Petals not observed.         -   Fragrance.—Moderately fragrant, pleasant.         -   Natural flowering season.—Early and long flowering period;             plants flower from mid-November to February in Germany.         -   Flower longevity on the plant.—About three weeks; flowers             persistent.         -   Flower buds.—Length: About 1 cm to 2 cm. Diameter: About 6             mm to 10 mm. Shape: Ovoid. Color: Between 155A to 145D.         -   Flowers.—Diameter: About 8 cm to 9 cm. Depth (height): About             2 cm.         -   Sepals.—Arrangement: Five in a single whorl. Length: About 4             cm to 4.5 cm. Width: About 3 cm to 4 cm. Shape: Broadly             ovate. Apex: Rounded. Base: Obtuse. Margin: Entire. Texture,             upper and lower surfaces: Smooth, glabrous; satiny. Color:             When opening and fully opened, upper surface: Close to             NN155D; color becoming closer to 145C to 145A with             development; basal spot, close to 144A to 144B. When opening             and fully opened, lower surface: Close to NN155D; basal             spot, close to 144B.         -   Peduncles.—Strength: Strong. Length: About 15 cm. Diameter:             About 3 mm to 5 mm. Aspect: Mostly upright. Texture: Smooth,             glabrous. Color: Close to 145B overlain with close to 183B.         -   Reproductive organs.—Stamens: Quantity per flower:             About 100. Anther shape: Elliptical. Anther length: About 1             mm to 2 mm. Anther color: Close to 3B. Pollen amount: None             observed. Pistils: Quantity per flower: About six to nine.             Pistil length: About 1.5 cm. Stigma shape: Pointed. Stigma             color: Close to 155A. Style length: About 8 mm. Style color:             Close to 155A. Ovary color: Close to 150D. Nectaries:             Quantity per flower: About twelve. Length: About 8 mm to             9 mm. Shape: Incurved. Color: Towards the base, close to             144C; towards the apex, close to 8A. Seeds/fruits: Seed and             fruit development have not been observed. -   Garden performance: Plants of the new Helleborus have been observed     to have good garden performance and to tolerate rain, wind and     temperatures from about −10° C. to about 36° C. -   Pathogen/pest resistance: Plants of the new Helleborus have not been     shown to be resistant to pathogens and pests common to Helleborus. 

1. A new and distinct Helleborus plant named ‘COSEH 210’ as illustrated and described. 